Option C: "Injuries can also occur when someone does not stretch properly or does not wear the proper equipment" is the most effective sentence as it provides specific supporting evidence related to the various causes of sports injuries, aligning with the passage's main idea that such injuries can impact individuals across different age groups and activities.
The most effective sentence at providing supporting evidence for the passage's main idea is option C: "Injuries can also occur when someone does not stretch properly or does not wear the proper equipment." This sentence directly addresses the concept of sports injuries by highlighting specific factors contributing to their occurrence—namely, insufficient stretching or inadequate use of proper equipment during physical activity.
Option C aligns with the main idea by emphasizing that sports injuries are not exclusive to the act of playing a sport but can also result from factors like improper preparation or lack of appropriate gear. This expands the understanding of sports injuries beyond the immediate sports context, reinforcing the idea that anyone engaged in physical activity can be susceptible to injuries.
On the contrary, option D does not contribute relevant evidence to the main idea of sports injuries affecting individuals of all ages. It provides information on employment growth, which is unrelated to the passage's focus on the universality of sports injuries.
Therefore, the correct option is C: "Injuries can also occur when someone does not stretch properly or does not wear the proper equipment".